Power transistors are commonly used to control high voltages and currents to a load. A power transistor may include a MOSFET or an Insulated Gate Bipolar Transistor (IGBT). Because a power transistor passes high voltage to a load, the MOSFET source may "float" over a voltage range from a low voltage to a high voltage. However, because the MOSFET gate must be biased with at least five volts greater than the source voltage, it becomes difficult to turn the power transistor ON.
To overcome the difficulty of turning ON the power transistor, several manufactures have used a transformer to control the power transistor bias. However a transformer is a costly circuit element. Moreover a transformer is bulky and radiates unwanted noise. Consequently such gate drive circuits are undesirable.
The present invention is directed to overcoming one or more of the problems as set forth above.